mcdonald



(No Model.) 3 SheetsSheet 1.

J'. H. MQDONALD.

GRAIN DRIER.

No. 368,298. Patented Aug. 16, 1887.

VVzmessesx lnvemor W his #vrney.

(No Model.) 3 Sheets-Sheet 2.

' J. H. MCDONALD.

GRAIN DRIER. No. 368,298. Patented Aug. 16, 1887.

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3 Sheets 3' {No del.)

J. H. MODONALD.

N0. 368,298. Patented Aug. 16, 1887.

.j mm m W mm H J /zz s AZZm m UNITED STATES JOSEPH H. MCDONALD,

PATENT GEE-lea.

OF NE\V YORK, N. Y.

GRAIN-DRIER.

SPECIFICATION forming part of Letters Patent No.368,298, dated August16, 1887.

Application filed November 24, 1886. Serial No. 219,836. (No model.)

To all whom it may concern.-

Be it k nown that i, J osnrn H. MCDONALD, a citizen of the UnitedStates, residing at New York, in the county of New York and State of NewYork, have invented certain new and useful Improvements in RotaryDriers; and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

This invention relates to dricrs, and particularly to that classdesigned for operation upon substances in a comminuted state.

The object is to produce a drier of comparatively uncomplicatedconstruction, and one by which a perfect drying of substances can beaccomplished.

The invention consists in a rotary dryingcylinder, rifled on itsinterior by flanges, buckets, or other suitable appliances, by which thematerial to be dried will be gradually advanced from one end of thecylinder to the other by a rotary motion of the same, and covered by acasing so arranged that there will be a space left between the cylinderand the casing, forming a jacket, and having entrance and exit passagesfor the admission and discharge of a suitable drying or absorbentaeriform fluid and provision for the admission and discharge of thematerial operated upon, combined with a furnace having a flue leadingdirectly under the cylinder and extending as an enlarged fire-bay thewholclength thereof, with its vent at the end opposite to that at whichit first enters, and with a damper and a branch flue, so that the heatand gases can be shut off from it, if required, and be diverted throughthe branch fiue directly up the chimney, the branch flue also containinga damper to prevent the escape of heat and gases through it when theyare needed in the process of dry ing and the other fine is open;furthermore, in combination with a drying-cylinder, a furnaceconstructed with double walls, or with an air-heating chamber, so thatinto the space between the walls or into the chamber air can beintroduced and there be heated, a conduit leading from this spacebetween the walls, or from the chamber to the end of the cylinderopposite that at which the moist material to branch to the furnace,thence through main flue or fire-box to chimney-stack, whereby a draftis created through the hot-air chamber, through the conduit leadingtherefrom to the cylinder, and thence through the entire cylinder; and,finally, in certain details of construction, all as hereinafter moreparticularly described, and pointed out in the claims.

In the accompanying drawings, forming part of this specification, and inwhich like letters of reference designate corresponding parts, Figure 1is a view of the drier in vertical longitudinal section, with thecylinder in elevation, showing the casing, provision for the admissionand discharge of the material operated upon, part ofthe supply-conduitfor the drying-fluid, and the furnace with its fine leading under thecylinderinto thcjacket, and, in dotted lines, the position of pipes andother parts of the apparatus. Fig. 2 is a plan view of the dryingapparatus with the cylinder removed,showingthehot-fluid-supplyconduit,or that leading from a metallic air-heating chamber in the wallsof the furnace toa position at the end of the cylinder opposite to thatat which the moist material to be operated upon isintroduced; also thefluid-discharge conduit, or that which when the cylinder is in placeleads from the end thereof at which the moist material is introduced tothe chimney; also the dampers in these conduits, and also, in dottedlines, the situation of the branch conduit, which leads to the lowerpart, so that, if de sired, the discharged aeriform fluid from thecylinder may be used to increase combustion in the furnace, this conduitalso having a passage for the hot air and gases from the. opposite endof the space beneath the cylinder. Fig. 3 is an elevation of the end ofthe apparatus at which the material is fed, showing the means forfeeding and rotating the cylinder, also showing the furnace with anentrance-port for the introduction ofair into the metallic air-heatingchamber, also showing the fluid-discharge conduit leading to the chimneyfrom this end of the cylinder and the branch conduit leading from thefluid-discharge conduit to the furnace. Fig. 4 is a verticalcross-section of the apparatus taken on theline 0c acof Fig. 1, showingthe cylinder with the flanges or buckets on its interior, theentrance-passage for the admission of the drying or absorbent aeriformfluid, and the casing covering the cylinder leaving the space betweenthe two; also showing the flue leading directly from the furnace underthe cylinder, extending as an enlarged fire-bay the whole lengththereof, with its vent at the oppositeend and. its damper; also showingthe branch flue with its damper; also showing, partly in dotted lines,the branch conduit leading to the furnace; also the metallic air-heatingchamber with damper in entrance of passage for heated gases to main fluefrom furnace, and also, in dotted lines, the hot-air conduit leadingfrom this metallic air-heating chamber to the cylinder.

This drier consists, primarily, of a cylinder, A, constructed to rotateon its axis, supported upon proper gearing, and arranged with suitablemechanism connected with power to give it the rotary motion. Theinterior of the cylinder is rifled by flanges or suitable buck. ets, a,or by other appliances by which the material to be dried is graduallyadvanced by the rotary motion from one end of the cylinder at which itis introduced by a conveyer in a small pipe surrounded by the exit-pipeto the other, from which it escapes in a dried state. To assist theprogress of the material it has generally been found best to set thecylinder upon a slight incline.

Closely adjoining the cylinder, and as near as convenient to the end atwhich the wet, moist, or undried material is introduced, is constructeda furnace, B, with a flue, B, which leads directly under the cylinder atthe end at which the moist materialv is introduced, and, extending as anenlarged fire-bay the whole length of the cylinder, it has its vent B atthe opposite end to that at which it enters, and connects with thechimney in any usual manner, or, as shown in dotted lines in Fig. 2 ofthe drawings, by a fine, B.

The cylinder is covered with a casing, C, so arranged that the hot airand products of combustion from the fiu-e B can circulate in a spaceleft between the casing and the cylinder, and so warm the entirecylinder. This casing or jacket is provided with packing collars orflanges c a near the ends of the cylinder, made with proper material tofit closely to the cylinder and retain the heat within the jacket, whileat the same time the ends of the cylinder project sufficiently to allowits gearing and the mechanism for its rotation to be in the coolatmosphere.

A damper is placed in the flue B, so that the heat and gases can be shutoff from be flue, B is constructed in such manner that un der thesecircumstances the heat and products of combustion can be diverted anddrawn directly up the chimney. A damper in this products of combustionthrough it when it is required that these should pass through the flue Bto the place about the cylinder.

The furnace B is constructed with an airheating chamber, D, preferablymetallic, so that air introduced, as bya door or port, (I, may beheated. This space or chamber coustitutes a hot-air box, which forms thearch, side, and back end of the furnace, with passages or flues E underand over it for the circulation of the heated gases, so that airintroduced into the chamber D may be readily heated to ahightemperature. A conduit, D,

the wet material is introduced, and by this means the air which has beenheated is conducted to the cylinder. This passageD constitutes ahot-air-supply conduit. Another conduit, D, leads from the end of thecylinder into which the wet material is introduced to the chimney-stack,and by this means a draft is created through the hot-air box, throughthe hot-air-supply conduit, alongv the entire length of the cylinder,and'thence to the open air. The passage D constitutes a fluid-dischargeconduit.

The pipe E, containing a screw conveyer, e, leads from ahopper, E,through the beginning or an elbow of the fluid-discharge conduit, and asthe gases and vapors which find their exit throngh this conduit will behot, the material to be dried as it passes through the feed-pipe E willbe heated before its introduction into the cylinder, thus utilizingwaste heat, and presenting the material in a condition immediately tocommence parting with its moisture. Furthermore, by the arrangement ofthe hot air-supply conduit and the fluid-discharge conduit with thecylinder, a current of heated air passes through the cylinder in adirection opposite to that to which the material is carried in thedrying process, and this heated air, like a sponge, absorbs the moisturefrom the ma terial under treatment and carries it away.

From that part of the fluid-discharge conduit which leads to thechimney-stack there may be a branch, D leading into the lower part ofthe furnace fire-box, so that, ifdesired, the moistened air and gasesgiven off from the material under treatment may be led to the furnace toincrease combustion therein. If

this branch conduit be employed,proper dampers should be placed thereinand in the fluiddischarge conduit, so that the moist air and neath thecylinder, if required, and a branch branch flue prevents the escape ofheat and leads from this chamber or hot-air box to the end of thecylinder opposite to that at which 4 gases given off from the materialin process of treatment can be sent directly to the stack of thechimney, or into the fire-box, as desired.

If the evaporation of the moisture in the material treated requires agreater amount of heat than can be supplied by a single furnace, asecond furnace may be built adjoining the cylinder at the same end asthe one shown, and on the opposite side, or at the other end of thecylinder, care being taken that the flues are so arranged that noconflict in the draft shall arise.

Having thus described my invention,what I claim, and desire to secure byLetters Patent, 1s-

1. A jacketed rotary drying-cylinder rifled on its interior by flangesor buckets, having entrance and exit passages for the admission anddischarge of a suitable drying or absorbent aeriform fluid and provisionfor the admission and discharge of the material operated upon, incombination with a furnace having a flue containing a damper and leadingto the space about the cylinder, and a branch flue, also containing adamper and leading directly to the chimney, the furnace having anairheating chamber, and there being a conduit leading from theair-heating chamber to one end of the cylinder, and another conduitpassing from the other end of the cylinder to the chimney-stack or by abranch to the furnace, substantially as and for the purpose described.

2. Thecombinatiomwith a jacketed dryingcylinder, of a furnaceconstructed with an airheating chamber having passages or flues underand over it, a conduit leading from the chamber to the end ofthedrying-cylinder, and another conduit leading from the cylinderdirectlytothe chimney, both conduits being provided with dampers,whereby the heated air may be passed into the cylinder and'directly upto the chimney or to the fires and flues B B", into which the productsof combustion may pass, both flues being provided with dampers, wherebythe products ofcombustion employed in heating the chamber may be used toheat the exterior of the cylinder, and thus aid the hot air supplied tothe interior for drying or be passed off direct to the chimney,substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JOSEPH H. MCDONALD.

VVi tn esses:

WM. H. S'rocKWELL, R0131. M. JOHNSTON.

